Machines, such as, for example, on-highway vehicles, off-highway vehicles, engines, and generators, may include electronic control systems having one or more electronic control units, sensors, and actuators. The electronic control systems and related electrical components may be interconnected using a network of conductors and electrical connectors to form one or more circuits.
Over time, the electrical devices, wires, and connectors may break, causing discontinuities to appear in the circuits. The discontinuities, sometimes referred to as “hard faults,” may inhibit or prevent electrical current from reaching portions of the electrical system. The lack of current may result in a degradation in machine performance or total machine failure. Even if the electrical devices, wires, and connectors do not completely break, they may still experience intermittent faults caused by such things as wear, machine vibration, chafing at electrical terminals, and entry of moisture into the electrical system. Unlike hard faults, intermittent faults may appear and then disappear, and sometimes, may appear for only fractions of a second. Additionally, intermittent faults may occur seemingly at random. For these reasons, intermittent faults may be more difficult to identify and diagnose than hard faults. Furthermore, some diagnostic devices used for diagnosing and identifying hard faults may characterize intermittent faults as false errors, and accordingly, intermittent faults may be ignored or overlooked.
At least one system has been developed for diagnosing machine electrical systems. For example, U.S. Pat. No. 6,477,478 to Jones et al. (“Jones”) discloses an apparatus, which comprises a base station and a handset, used for vehicle testing. The handset is adapted to carry out a test sequence under the control of the base station. A test sequence performed using the apparatus includes shaking the vehicle or starting and stopping the vehicle's engine several times. Significant variations in measurements indicate intermittent problems and their severity. The starting and stopping of the engine, however, may cause vibrations in the vehicle's electrical system. The vibrations may cause intermittent faults to appear simultaneously in multiple areas of the electrical system, thus making the separate identification of each intermittent fault more difficult. Failing to particularly identify intermittent faults may result in unnecessary repairs. Also, if an intermittent fault prevents the engine from starting in the first place, then the test sequence may fail to execute properly. Furthermore, shaking the vehicle may require a great deal of effort, while also increasing the likelihood of causing damage to other components of the vehicle.
The disclosed apparatus is directed to overcoming one or more of the problems set forth above.